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o-Toluidine

May 1994

Immediately Dangerous to Life or Health Concentrations (IDLH)

NIOSH REL: None established; NIOSH considers o-toluidine to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990] that may be absorbed through the skin.

Current OSHA PEL: 5 ppm (22 mg/m3) TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 2 ppm (8.8 mg/m3) TWA [skin], A2

Description of substance: Colorless to pale-yellow liquid with an aromatic, aniline-like odor.

LEL: . . Unknown

Original (SCP) IDLH: 100 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Sax [1975] that 100 ppm is the maximum concentration endurable for 1 hour without serious consequences. No other data are available on which to base the IDLH.

Human data: It has been reported that a 60-minute exposure to 40 ppm produces severe toxic effects [Goldblatt 1955]. It has been reported that 100 ppm is the maximum concentration endurable for 1 hour without serious consequences [Sax 1975].

Revised IDLH: 50 ppm

Basis for revised IDLH: The revised IDLH for o-toluidine is 50 ppm based on acute inhalation toxicity data in humans [Goldblatt 1955; Sax 1975]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for o-toluidine at any detectable concentration.]

2. IARC [1982]. ortho-Toluidine and its hydrochloride. In: IARC monographs on the evaluation of carcinogenic risk of chemicals to humans. Vol. 27. Some aromatic amines, anthraquinones and nitroso compounds, and inorganic fluorides used in drinking-water and dental preparations, pp. 155-175.